'Internal Error'

I am having a problem trying to ‘Export to XPlane’ one of my Airport building and get the posted error message.
But this is the only one that gets this error I have built two other buildings and had no problems at all.
Any help is very much appreciated.Capture

Have you run Purge Unused and Fix Problems on this model?

Did you try quitting and restarting SketchUp to see if that took care of the problem?

I’m not familiar with the requirements of the exporter for XPlane but does it care about face orientation? If so, are there exposed reversed faces? Possibly a texture image that is bad or incorrectly applied? All just guessing since we have nothing to go on but a screen shot of a cryptic error message.

Thanks for the reply Dave. Problem is fixed! It was an ‘Nested Instance’ which Solid Inspector couldn’t fix.
But It was the smallest NI so had to really look for it! So now the Building has been able to export.